Pruning

The blockchain prunes seven eighths of prunable tx data.
This saves about two thirds of the blockchain size, while
keeping the node useful as a sync source for an eighth
of the blockchain.

No other data is currently pruned.

There are three ways to prune a blockchain:

- run monerod with --prune-blockchain
- run "prune_blockchain" in the monerod console
- run the monero-blockchain-prune utility

The first two will prune in place. Due to how LMDB works, this
will not reduce the blockchain size on disk. Instead, it will
mark parts of the file as free, so that future data will use
that free space, causing the file to not grow until free space
grows scarce.

The third way will create a second database, a pruned copy of
the original one. Since this is a new file, this one will be
smaller than the original one.

Once the database is pruned, it will stay pruned as it syncs.
That is, there is no need to use --prune-blockchain again, etc.

4 files changed, 245 insertions, 0 deletions

diff --git a/tests/core_proxy/core_proxy.h b/tests/core_proxy/core_proxy.h
index 023c220ae..7888540cc 100644
--- a/tests/core_proxy/core_proxy.h
+++ b/tests/core_proxy/core_proxy.h
@@ -105,5 +105,7 @@ namespace tests
     bool fluffy_blocks_enabled() const { return false; }
     uint64_t prevalidate_block_hashes(uint64_t height, const std::vector<crypto::hash> &hashes) { return 0; }
     bool pad_transactions() const { return false; }
+    uint32_t get_blockchain_pruning_seed() const { return 0; }
+    bool prune_blockchain(uint32_t pruning_seed) const { return true; }
   };
 }
diff --git a/tests/unit_tests/CMakeLists.txt b/tests/unit_tests/CMakeLists.txt
index f7012746d..5f7fa84a5 100644
--- a/tests/unit_tests/CMakeLists.txt
+++ b/tests/unit_tests/CMakeLists.txt
@@ -65,6 +65,7 @@ set(unit_tests_sources
   notify.cpp
   output_distribution.cpp
   parse_amount.cpp
+  pruning.cpp
   random.cpp
   serialization.cpp
   sha256.cpp
diff --git a/tests/unit_tests/ban.cpp b/tests/unit_tests/ban.cpp
index 12625a949..1e764c83e 100644
--- a/tests/unit_tests/ban.cpp
+++ b/tests/unit_tests/ban.cpp
@@ -84,6 +84,8 @@ public:
   bool fluffy_blocks_enabled() const { return false; }
   uint64_t prevalidate_block_hashes(uint64_t height, const std::vector<crypto::hash> &hashes) { return 0; }
   bool pad_transactions() { return false; }
+  uint32_t get_blockchain_pruning_seed() const { return 0; }
+  bool prune_blockchain(uint32_t pruning_seed = 0) { return true; }
   void stop() {}
 };
 
diff --git a/tests/unit_tests/pruning.cpp b/tests/unit_tests/pruning.cpp
new file mode 100644
index 000000000..83c35df68
--- /dev/null
+++ b/tests/unit_tests/pruning.cpp
@@ -0,0 +1,240 @@
+// Copyright (c) 2018, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "gtest/gtest.h"
+
+#include "misc_log_ex.h"
+#include "cryptonote_config.h"
+#include "common/pruning.h"
+
+#define ASSERT_EX(x) do { bool ex = false; try { x; } catch(...) { ex = true; }  ASSERT_TRUE(ex); } while(0)
+
+TEST(pruning, parts)
+{
+  ASSERT_EQ(tools::get_pruning_stripe(tools::make_pruning_seed(3, 2)), 3);
+  ASSERT_EQ(tools::get_pruning_stripe(tools::make_pruning_seed(1, 2)), 1);
+  ASSERT_EQ(tools::get_pruning_stripe(tools::make_pruning_seed(7, 7)), 7);
+
+  ASSERT_EQ(tools::get_pruning_log_stripes(tools::make_pruning_seed(1, 2)), 2);
+  ASSERT_EQ(tools::get_pruning_log_stripes(tools::make_pruning_seed(1, 0)), 0);
+  ASSERT_EQ(tools::get_pruning_log_stripes(tools::make_pruning_seed(1, 7)), 7);
+  ASSERT_EQ(tools::get_pruning_log_stripes(tools::make_pruning_seed(7, 7)), 7);
+
+  for (uint32_t log_stripes = 1; log_stripes <= tools::PRUNING_SEED_LOG_STRIPES_MASK; ++log_stripes)
+  {
+    for (uint32_t stripe = 1; stripe <= (1 << log_stripes); ++stripe)
+    {
+      ASSERT_EQ(tools::get_pruning_log_stripes(tools::make_pruning_seed(stripe, log_stripes)), log_stripes);
+      ASSERT_EQ(tools::get_pruning_stripe(tools::make_pruning_seed(stripe, log_stripes)), stripe);
+    }
+  }
+}
+
+TEST(pruning, out_of_range)
+{
+  ASSERT_EX(tools::make_pruning_seed(5, 2));
+  ASSERT_EX(tools::make_pruning_seed(0, 2));
+}
+
+TEST(pruning, fits)
+{
+  const uint32_t log_stripes = 3;
+  const uint32_t num_stripes = 1 << log_stripes;
+  for (uint32_t stripe = 1; stripe <= num_stripes; ++stripe)
+  {
+    const uint32_t seed = tools::make_pruning_seed(stripe, log_stripes);
+    ASSERT_NE(seed, 0);
+    ASSERT_EQ(tools::get_pruning_log_stripes(seed), log_stripes);
+    ASSERT_EQ(tools::get_pruning_stripe(seed), stripe);
+  }
+}
+
+TEST(pruning, tip)
+{
+  static constexpr uint64_t H = CRYPTONOTE_PRUNING_TIP_BLOCKS + 1000;
+  static_assert(H >= CRYPTONOTE_PRUNING_TIP_BLOCKS, "H must be >= CRYPTONOTE_PRUNING_TIP_BLOCKS");
+  for (uint64_t h = H - CRYPTONOTE_PRUNING_TIP_BLOCKS; h < H; ++h)
+  {
+    uint32_t pruning_seed = tools::get_pruning_seed(h, H, CRYPTONOTE_PRUNING_LOG_STRIPES);
+    ASSERT_EQ(pruning_seed, 0);
+    for (pruning_seed = 0; pruning_seed <= (1 << CRYPTONOTE_PRUNING_LOG_STRIPES); ++pruning_seed)
+      ASSERT_TRUE(tools::has_unpruned_block(h, H, pruning_seed));
+  }
+}
+
+TEST(pruning, seed)
+{
+  const uint64_t SS = CRYPTONOTE_PRUNING_STRIPE_SIZE;
+  const uint64_t NS = 1 << CRYPTONOTE_PRUNING_LOG_STRIPES;
+  const uint64_t TB = NS * SS;
+
+  for (uint64_t cycle = 0; cycle < 10; ++cycle)
+  {
+    const uint64_t O = TB * cycle;
+    ASSERT_EQ(tools::get_pruning_stripe(O + 0,       10000000, CRYPTONOTE_PRUNING_LOG_STRIPES), 1);
+    ASSERT_EQ(tools::get_pruning_stripe(O + 1,       10000000, CRYPTONOTE_PRUNING_LOG_STRIPES), 1);
+    ASSERT_EQ(tools::get_pruning_stripe(O + SS-1,    10000000, CRYPTONOTE_PRUNING_LOG_STRIPES), 1);
+    ASSERT_EQ(tools::get_pruning_stripe(O + SS,      10000000, CRYPTONOTE_PRUNING_LOG_STRIPES), 2);
+    ASSERT_EQ(tools::get_pruning_stripe(O + SS*2-1,  10000000, CRYPTONOTE_PRUNING_LOG_STRIPES), 2);
+    ASSERT_EQ(tools::get_pruning_stripe(O + SS*2,    10000000, CRYPTONOTE_PRUNING_LOG_STRIPES), 3);
+    ASSERT_EQ(tools::get_pruning_stripe(O + SS*NS-1, 10000000, CRYPTONOTE_PRUNING_LOG_STRIPES), NS);
+    ASSERT_EQ(tools::get_pruning_stripe(O + SS*NS,   10000000, CRYPTONOTE_PRUNING_LOG_STRIPES), 1);
+  }
+}
+
+TEST(pruning, match)
+{
+  static constexpr uint64_t H = CRYPTONOTE_PRUNING_TIP_BLOCKS + 1000;
+  static_assert(H >= CRYPTONOTE_PRUNING_TIP_BLOCKS, "H must be >= CRYPTONOTE_PRUNING_TIP_BLOCKS");
+  for (uint64_t h = 0; h < H - CRYPTONOTE_PRUNING_TIP_BLOCKS; ++h)
+  {
+    uint32_t pruning_seed = tools::get_pruning_seed(h, H, CRYPTONOTE_PRUNING_LOG_STRIPES);
+    uint32_t pruning_stripe = tools::get_pruning_stripe(pruning_seed);
+    ASSERT_TRUE(pruning_stripe > 0 && pruning_stripe <= (1 << CRYPTONOTE_PRUNING_LOG_STRIPES));
+    for (uint32_t other_pruning_stripe = 1; other_pruning_stripe <= (1 << CRYPTONOTE_PRUNING_LOG_STRIPES); ++other_pruning_stripe)
+    {
+      uint32_t other_pruning_seed = tools::make_pruning_seed(other_pruning_stripe, CRYPTONOTE_PRUNING_LOG_STRIPES);
+      ASSERT_TRUE(tools::has_unpruned_block(h, H, other_pruning_seed) == (other_pruning_seed == pruning_seed));
+    }
+  }
+}
+
+TEST(pruning, stripe_size)
+{
+  static constexpr uint64_t H = CRYPTONOTE_PRUNING_TIP_BLOCKS + CRYPTONOTE_PRUNING_STRIPE_SIZE * (1 << CRYPTONOTE_PRUNING_LOG_STRIPES) + 1000;
+  static_assert(H >= CRYPTONOTE_PRUNING_TIP_BLOCKS + CRYPTONOTE_PRUNING_STRIPE_SIZE * (1 << CRYPTONOTE_PRUNING_LOG_STRIPES), "H must be >= that stuff in front");
+  for (uint32_t pruning_stripe = 1; pruning_stripe <= (1 << CRYPTONOTE_PRUNING_LOG_STRIPES); ++pruning_stripe)
+  {
+    uint32_t pruning_seed = tools::make_pruning_seed(pruning_stripe, CRYPTONOTE_PRUNING_LOG_STRIPES);
+    unsigned int current_run = 0, best_run = 0;
+    for (uint64_t h = 0; h < H - CRYPTONOTE_PRUNING_TIP_BLOCKS; ++h)
+    {
+      if (tools::has_unpruned_block(h, H, pruning_seed))
+      {
+        ++current_run;
+      }
+      else if (current_run)
+      {
+        ASSERT_EQ(current_run, CRYPTONOTE_PRUNING_STRIPE_SIZE);
+        best_run = std::max(best_run, current_run);
+        current_run = 0;
+      }
+    }
+    ASSERT_EQ(best_run, CRYPTONOTE_PRUNING_STRIPE_SIZE);
+  }
+}
+
+TEST(pruning, next_unpruned)
+{
+  static_assert((1 << CRYPTONOTE_PRUNING_LOG_STRIPES) >= 4, "CRYPTONOTE_PRUNING_LOG_STRIPES too low");
+
+  const uint64_t SS = CRYPTONOTE_PRUNING_STRIPE_SIZE;
+  const uint64_t NS = 1 << CRYPTONOTE_PRUNING_LOG_STRIPES;
+  const uint64_t TB = NS * SS;
+
+  for (uint64_t h = 0; h < 100; ++h)
+    ASSERT_EQ(tools::get_next_unpruned_block_height(h, 10000000, 0), h);
+
+  const uint32_t seed1 = tools::make_pruning_seed(1, CRYPTONOTE_PRUNING_LOG_STRIPES);
+  const uint32_t seed2 = tools::make_pruning_seed(2, CRYPTONOTE_PRUNING_LOG_STRIPES);
+  const uint32_t seed3 = tools::make_pruning_seed(3, CRYPTONOTE_PRUNING_LOG_STRIPES);
+  const uint32_t seed4 = tools::make_pruning_seed(4, CRYPTONOTE_PRUNING_LOG_STRIPES);
+  const uint32_t seedNS = tools::make_pruning_seed(NS, CRYPTONOTE_PRUNING_LOG_STRIPES);
+
+  ASSERT_EQ(tools::get_next_unpruned_block_height(0,      10000000, seed1), 0);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(1,      10000000, seed1), 1);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(SS-1,   10000000, seed1), SS-1);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(SS,     10000000, seed1), TB);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(TB,     10000000, seed1), TB);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(TB-1,   10000000, seed1), TB);
+
+  ASSERT_EQ(tools::get_next_unpruned_block_height(0,      10000000, seed2), SS);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(1,      10000000, seed2), SS);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(SS-1,   10000000, seed2), SS);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(SS,     10000000, seed2), SS);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(2*SS-1, 10000000, seed2), 2*SS-1);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(2*SS,   10000000, seed2), TB+SS);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(TB+2*SS,10000000, seed2), TB*2+SS);
+
+  ASSERT_EQ(tools::get_next_unpruned_block_height(0,      10000000, seed3), SS*2);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(SS,     10000000, seed3), SS*2);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(2*SS,   10000000, seed3), SS*2);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(3*SS-1, 10000000, seed3), SS*3-1);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(3*SS,   10000000, seed3), TB+SS*2);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(TB+3*SS,10000000, seed3), TB*2+SS*2);
+
+  ASSERT_EQ(tools::get_next_unpruned_block_height(SS,     10000000, seed4), 3*SS);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(4*SS-1, 10000000, seed4), 4*SS-1);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(4*SS,   10000000, seed4), TB+3*SS);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(TB+4*SS,10000000, seed4), TB*2+3*SS);
+
+  ASSERT_EQ(tools::get_next_unpruned_block_height(SS,     10000000, seedNS), (NS-1)*SS);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(NS*SS-1,10000000, seedNS), NS*SS-1);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(NS*SS,  10000000, seedNS), TB+(NS-1)*SS);
+  ASSERT_EQ(tools::get_next_unpruned_block_height(TB+NS*SS,  10000000, seedNS), TB*2+(NS-1)*SS);
+}
+
+TEST(pruning, next_pruned)
+{
+  static_assert((1 << CRYPTONOTE_PRUNING_LOG_STRIPES) >= 4, "CRYPTONOTE_PRUNING_LOG_STRIPES too low");
+
+  const uint64_t SS = CRYPTONOTE_PRUNING_STRIPE_SIZE;
+  const uint64_t NS = 1 << CRYPTONOTE_PRUNING_LOG_STRIPES;
+  const uint64_t TB = NS * SS;
+
+  const uint32_t seed1 = tools::make_pruning_seed(1, CRYPTONOTE_PRUNING_LOG_STRIPES);
+  const uint32_t seed2 = tools::make_pruning_seed(2, CRYPTONOTE_PRUNING_LOG_STRIPES);
+  const uint32_t seedNS_1 = tools::make_pruning_seed(NS-1, CRYPTONOTE_PRUNING_LOG_STRIPES);
+  const uint32_t seedNS = tools::make_pruning_seed(NS, CRYPTONOTE_PRUNING_LOG_STRIPES);
+
+  for (uint64_t h = 0; h < 100; ++h)
+    ASSERT_EQ(tools::get_next_pruned_block_height(h, 10000000, 0), 10000000);
+  for (uint64_t h = 10000000 - 1 - CRYPTONOTE_PRUNING_TIP_BLOCKS; h < 10000000; ++h)
+    ASSERT_EQ(tools::get_next_pruned_block_height(h, 10000000, 0), 10000000);
+
+  ASSERT_EQ(tools::get_next_pruned_block_height(1,    10000000, seed1), SS);
+  ASSERT_EQ(tools::get_next_pruned_block_height(SS-1, 10000000, seed1), SS);
+  ASSERT_EQ(tools::get_next_pruned_block_height(SS,   10000000, seed1), SS);
+  ASSERT_EQ(tools::get_next_pruned_block_height(TB-1, 10000000, seed1), TB-1);
+  ASSERT_EQ(tools::get_next_pruned_block_height(TB,   10000000, seed1), TB+SS);
+
+  ASSERT_EQ(tools::get_next_pruned_block_height(1,    10000000, seed2), 1);
+  ASSERT_EQ(tools::get_next_pruned_block_height(SS-1, 10000000, seed2), SS-1);
+  ASSERT_EQ(tools::get_next_pruned_block_height(SS,   10000000, seed2), 2*SS);
+  ASSERT_EQ(tools::get_next_pruned_block_height(TB-1, 10000000, seed2), TB-1);
+
+  ASSERT_EQ(tools::get_next_pruned_block_height(1,    10000000, seedNS_1), 1);
+  ASSERT_EQ(tools::get_next_pruned_block_height(SS-1, 10000000, seedNS_1), SS-1);
+  ASSERT_EQ(tools::get_next_pruned_block_height(SS,   10000000, seedNS_1), SS);
+  ASSERT_EQ(tools::get_next_pruned_block_height(TB-1, 10000000, seedNS_1), TB-1);
+
+  ASSERT_EQ(tools::get_next_pruned_block_height(1,    10000000, seedNS), 1);
+  ASSERT_EQ(tools::get_next_pruned_block_height(SS-1, 10000000, seedNS), SS-1);
+  ASSERT_EQ(tools::get_next_pruned_block_height(SS,   10000000, seedNS), SS);
+  ASSERT_EQ(tools::get_next_pruned_block_height(TB-1, 10000000, seedNS), TB);
+}